St John’s College, Oxford, and the new Ynysowen Community Primary School in South Wales, are being fitted with ground source heat pump technology, which will cut costs and boost environmental benefits.

The 280-pupil school, near Aberfan, and the 500-student college are among a growing number of educational establishments using ground source heat pumps to harness solar energy absorbed by the earth as a cheap and reliable source of renewable energy.

By using the relatively stable temperatures found under the earth’s surface, ground source heat pump systems deliver efficient heating and cooling, say manufacturers.

A heat exchanger made up of a network of polyethylene pipes is buried underground to transfer energy to or from the earth via a heat pump.

The heat pumps come in different styles and heat or cool buildings by various water or air distribution systems, including under floor heating, radiators, fan coils and ducted air systems.

The ground source system being put in at St John’s College’s new Kendrew Quadrangle development this summer involves 48 boreholes and heat pumps with combined capacities of 146kW for heating and 115kW for cooling.

It is expected to result in annual carbon savings of around 17 tonnes, equivalent to the environmental benefit of 1,700 trees.

Ynsowen’s ground source heating system employs 14 boreholes and a total heat pump capacity of 74kW and is expected to yield annual carbon savings of four tonnes – equal to the environmental benefit of 400 trees.

The new school opened in April covers 2,000m² and comprises 14 classrooms, an IT suite, library and assembly hall.

The ENER-G geothermal technology is being used in other schools, including Galston Primary School in East Ayrshire, Redhill Primary School in Worcestershire, and Ashfield Skills Centre at Ashfield School in Nottinghamshire.

David Gibbs

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